As a related-art control device for an AC rotary machine, as disclosed in Patent Literature 1 and Patent Literature 2, there is known a control device configured to perform sensor-less control by estimating a velocity and a position of a rotor based on a resistance value of winding and using those estimated values instead of signals detected by a position sensor and a velocity sensor.
Further, as another invention, as disclosed in Patent Literature 3, there is known a control device configured to accurately estimate the resistance value of winding, which changes depending on temperature, with use of an external temperature of the AC rotary machine and a current value of an armature.